To arrive at a more precise figure, my colleagues and I developed a tool, as reported in a recent paper , that uses satellite imagery to evaluate in real time all 42 of the oil production sites once controlled by ISIS. The results show that production levels were approximately 56,000 barrels per day from July to December 2014. Production dropped to an average of 35,000 barrels per day throughout 2015, before declining further to approximately 16,000 barrels per day in 2016. Why it matters: Our study shows that ISIS has been highly ineffective in managing its oil fields, limiting its revenue from these valuable assets and forcing it to fall back on taxation and extortion for funding. This data can also help to shape plans for rebuilding areas liberated from ISIS control by setting priorities for needed repairs and providing revenue projections for local economies.